<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
</head>
<body>
    <button onclick="funAutoAdd()">自增</button>
    <button onclick="funAutoSub()">自减</button>
</body>
    <script>
        function funAutoAdd(){
            a = 10
            console.log(a++)
            console.log(a)
        }
        function funAutoSub(){
            a = 10
            a--
            console.log(a)
        }
    </script>
</html>